Device for testing for {37 frosting{38 {0 in fabrics

ABSTRACT

&#39;&#39;&#39;&#39;Frosting&#39;&#39;&#39;&#39; on dyed fabrics, which indicates abrasive wear, is measured by abrading a rotating sample of fabric in a closed chamber, illuminating the abraded area, and scanning the illuminated area with a photoelectric sensing device. The signal generated by the latter is fed into recording means. Graphic evaluation of a plurality of fabrics compares favorably with subjective evaluation of the same fabrics by accepted methods. Reproducibility of measurement is excellent.

United States Patent Truman L. Ward New Orleans;

Ralph J. Berni, Metairie; Julius R. Jung,

J r., New Orleans; Ruth R. Benerito, New Orleans, all of La.

Dec. 22, 1969 Oct. 12, 1971 The United States of America as representedby the Secretary of Agriculture Inventors Appl. No. Filed PatentedAssignee DEVICE FOR TESTING FOR FROSTING" IN FABRICS 3 Claims, 6 DrawingFigs.

US. Cl 250/222, 250/219 F, 73/7, 26/28 Int. Cl G01n 3/56 Field of Search250/211,

References Cited UNITED STATES PATENTS Carpenter et a1. Snow I-loodStrong Coleman Ros Flower Edmonds Primary Examiner-Walter StolweinAttorneys-R. Hoffman and W. Bier ABSTRACT: Frosting on dyed fabrics,which indicates abrasive wear, is measured by abrading a rotating sampleof fabric in a closed chamber, illuminating the abraded area,andscanning the illuminated area with a photoelectric sensing device.The signal generated by the latter is fed into recording means. Graphicevaluation of a plurality of fabrics compares favorably with subjectiveevaluation of the same fabrics by accepted methods. Reproducibility ofmeasurement is excellent.

PATENTEUUBT 12' Ian SHEET 16F 4 FIG] ATTORNEY PATENTED 12 3.612 891SHEET 2 [IF 4 INVENTORS TRUMAN L. WARD RALPH J. BERN! JULIUS R.JUNG,JR.,RUTH RBENERITO BY l 2 Z I q.

ATTORNEY PAIENTED um 12 I9?! 3. 6 l 2 891 SHEET 3 BF 4 INVENTORS TRUMANL. WA RALPH J. BERNI JULIUS R. JUN R, RUTH RBENERITO ATTORNEY PATENTEUum12 nan SHEET u nr 4 INVENTORS TRUMAN L. WARD RALPH J. BERN! MIUSR.JUNG,JR., RUTH RENERITO ATTORNEY DEVICE FOR TESTING FOR FROSTING" INFABRICS A nonexclusive, irrevocable, royalty-free license in theinvention herein described throughout the world for all purposes of theUnited States Government, with the power to grant sublicenses for suchpurposes, is hereby granted to the Government of the United States ofAmerica.

This invention relates to a device for measuring frosting in dyedfabrics. The term frosting" is used in textile testing to determine theresistance to abrasion which may have been imparted to a fabric.Differential wear or fibrillation of a fabric produces this frosting.Change in fabric color or shade caused by localized abrasive wear isgenerally the manifestation of the breakage of dyed fibers. When thedyeing is mainly on the surface of a fiber the undyed cross sectiontends to fray at the end where abrasion has caused breakage, and whenenough of these frayed ends are viewed at armslength there is a frosty"appearance. If the dyeing is within as well as on the surface of a fiberthe abraded portion of a fabric of such nature tends to produce a darkerfrosting. The device and method of this invention provide a means formeasuring the amount of abrasion by correlating the light reflectancewith such abrasion. The reflectance can be read through an ordinaryreflectometer or it can be fed to a recording device in order to obtaina graphic representation, and a correlation of wear against number ofcycles required to obtain a certain amount of abrasion. This data can inturn be used comparatively against another similar fabric to determinewhether a certain dyeing is efiicient, whether a certain dye issuitable, a certain temperature, a certain fabric construction, orwhether a certain blend should be attempted before large quantities areproduced.

Well-known and accepted subjective methods for measuring frosting aredescribed in Tentative Test Methods 1 19- l 967 and l20-I967 of theAmerican Association of Textile Chemists and Colorists Technical Manual43 (1967). These methods were considered acceptable by the varioustextile industries for many years. As the art of textile dyeing advancedit became imperative to institute more accurate and precise ways ofprocessing. Fast and repetitive means of quality and quantity controlsmust be instituted to keep pace with the demands of the economy. Thisinvention provides a means of fulfilling these needs.

The main object of this invention is to provide a means and method ofobtaining objective evaluation of the resistance dyed fabric samples tofrosting during flat abrasion.

A second object of the instant invention is to provide a less subjectivemeans of rapidly and repetitively evaluating the performance of fabricsunder flat abrasion testing while the testing is still in operation.

The above objects are achieved by adapting a commercially available flatabrader unit for use with a reflectance measuring unit.

The method itself consists of abrading a rotating dyed fabric sample andcontinuously monitoring the results of abrasion by employing aphotoelectric cell in conjunction with a galvanometer or a continuousrecording means. The degree of frosting is then measured as the frostingis being produced. Known methods employ static evaluation aftercompletion of the abrasion rather than during the abrasion.

In general, this invention comprises a light-tight chamber in which areenclosed a rotating abrading unit adapted to be brought into contactwith a sample of dyed fabric secured to a rotatable flat turntable. Areflectance unit, which comprises a source of light and a photoelectricsensing device, is also enclosed within the light-tight chamber. Thisreflectance unit is so located that it can be swung into position toilluminate the abraded area of the sample. Light reflected from thesample is intercepted by the photoelectric sensing means which generatesa signal whose intensity is a function of the reflected light. Thegenerated signal may be measured by an externally connected galvanometeror it may be directed to an externally connected recording device whichwill produce a permanent, continuous chart of the signal strengthvariations during the course of an abrading test. A suction tube,connected to an extemal source of vacuum, is mounted in proximity to thefabric surface being abraded to remove lint.

In order that the invention may be more readily understood, reference ismade to the following detailed description and to the accompanyingdrawings in which:

FIG. 1 is an elevation, with the container removed, schematicallyshowing the relative placement of the essential elements of theapparatus;

FIG. 2 is a top view as observed from plane 2-2 ofFlG. 1;

FIG. 3 is an auxiliary schematic sectional elevation, taken on line 33of FIG. 2;

FIG. 4 is an overall perspective view of the device shown with the (overclosed and showing the location of the control switch;

FIG. 5 shows the completely assembled device with a test fabric in placeand the abrading means and illuminator in position for operation; and

FIG. 6 shows the device as in FIG. 5, except that the abrading andilluminating means are retracted.

As particularly shown in FIGS. 1 and 2, light rays 1 from lamp II areconverged by condensing lens 2 and made to pass through center ofphotocell 3. The light strikes the dyed fabric 4, which is kept free oflint by vacuum provided through vacuum line 5 placed at about from I to10 millimeters distance from the surface of the fabric sample to beabraded. The light rays 1 striking the abraded part of the surface ofthe fabric 4 are reflected into photocell 3 where light energy isconverted to electrical energy and read either as a unit of electricityon the face of galvanometer 20, connected in a known manner to photocell3 by means of line 21. If desired, a permanent record of variations inreflected light can be obtained as a graphical presentation bysubstituting a conventional XY recorder (not shown) in a manner wellknown to those skilled in the art. The circular fabric specimen 4 isheld in place on turntable 6 by concentric plate 7 (about 1% inches indiameter), fastened by thumbscrew 30 and by ring clamp 8 around theturntable.

Frosting of the dyed textile specimen (or sample) is accom plished byrotating the fabric sample under and against abrasion wheels 9, whichabrade, and thereby frost, a concentric circular path 10. The number ofcomplete rotations of the turntable 6 is monitored by means of aresettable cycle counter (not shown). Toggle switch 12 (FIGS. 4,5, and6) controls the electrical power to the turntable 6. The abrasion wheels9 and photocell holder 25 may be tilted out of the way. as shown in FIG.6, to facilitate the changing of fabric samples. Abrasion wheel supportarms 14 must also be lifted away from contact with the fabric surface 4in order to either place or remove the fabric sample. The abrasion wheelsupport anns 14 move out of the way by pivoting on pin 15, mounted inbrackets 28 and 29.

The photocell 3 receives primarily diffuse reflected light from afrosted area about 1% square centimeters rather than a point source, andit is essential that the sample be kept free of lint. Lint 16 is removedas it is being produced by the abrasive action of the instrument on thefabric surface 4 by vacuum line 5 which is connected to a vacuumproducing source (not shown). FIGS. 4, 5, and 6 show, respectively, theassembled instrument closed, open but otherwise ready for operation, andwith the abrader and illuminating units swung away. Toggle switch 12 isshown in the closed chamber of FIG. 4. These figures also illustratepictorially how the photocell assembly 17 may be tilted, and how theabrasion wheel support arms 14 can be lifted so that the fabric sample 4can be removed by removing the concentric plate 7 and the ring clamps 8which hold the sample in place.

An account of further uses of the above-described instrument has beenpublished by the present applicants in the paper entitled An Instrumentfor the Measurement of Frosting" in Textile Chemists and Colorists, Vol.I. No. 1. (Jan. 15, 1969).

We claim:

1. A method for measuring abrasion resistance of fabrics whichcomprises:

providing a sample of fabric dyed with a nonreactive dye; continuouslyabrading the surface of said dyed fabric in an enclosed, light-tightenvironment;

c. continuously removing generated lint from the surface of the fabricbeing abraded;

d. simultaneously illuminating said surface to produce a diffusedreflection; and

e. measuring the intensity of said diffused reflection to provide anindication of the extent to which dyed fibers were removed from thesurface of the fabric during abrasion.

2. Apparatus for measuring abrasion resistance of fabrics comprising alight-tight enclosure and, mounted within said enclosure:

a. a flat rotatable platform;

b. means for rotating said platform connected thereto;

c. means for securing a fabric sample to the platform;

d. abrading means pivotally mounted in proximity to the rotatableplatform said abrading means being positionable to be in contact withthe surface of a sample of fabric secured to said rotatable platform;

. illuminating means mounted in proximity to said rotatag. meansconnected to said photosensitive means for recording the generatedelectrical signal.

3. The apparatus of claim 5 wherein means are provided for continuouslyremoving lint from the surface of the fabric during abrasion.

1. A method for measuring abrasion resistance of fabrics whichcomprises: a. providing a sample of fabric dyed with a nonreactive dye;b. continuously abrading the surface of said dyed fabric in an enclosed,light-tight environment; c. continuously removing generated lint fromthe surface of the fabric being abraded; d. simultaneously illuminatingsaid surface to produce a diffused reflection; and e. measuring theintensity of said diffused reflection to provide an indication of theextent to which dyed fibers were removed from the surface of the fabricduring abrasion.
 2. Apparatus for measuring abrasion resistance offabrics comprising a light-tight enclosure and, mounted within saidenclosure: a. a flat rotatable platform; b. means for rotating saidplatform connected thereto; c. means for securing a fabric sample to theplatform; d. abrading means pivotally mounted in proximity to therotatable platform said abrading means being positionable to be incontact with the surface of a sample of fabric secured to said rotatableplatform; e. illuminating means mounted in proximity to said rotatableplatform so positioned as to direct light at the surface of a fabricsample secured to said platform; f. photosensitive means also inproximity to said platform for receiving diffused reflected light fromthe surface of a fabric sample being abraded and for generating anelectric signal which is a function of the intensity of the reflectedlight; and g. means connected to said photosensitive means for recordingthe generated electrical signal.
 3. The apparatus of claim 5 whereinmeans are provided for continuously removing lint from the surface ofthe fabric during abrasion.